SummaryOver the past two decades, a data-driven revolution has occurred in our understanding of the origin and evolution of our Universe and the structure within it. During this period, cosmology has evolved from a speculative branch of theoretical physics into precision science at the intersection of gravity, particle- and astrophysics. Despite all we have learned, we still do not understand why the Universe accelerates, and how the structure in the Universe originated. Recent breakthrough research, with leading contributions by the PI of this proposal, has shown that we can make progress on these questions using observations of the large-scale structure and its tracers, galaxies. This opens up a fascinating, new interdisciplinary research field: probing Gravity and Inflation with Galaxies. The goal of the proposed research is to first, probe our theory of gravity, General Relativity, on cosmological scales. Second, it aims to shed light on the origin of the initial seed fluctuations out of which all structure in the Universe formed, by constraining the physics and energy scale of inflation. While seemingly unrelated, the main challenge in both research directions consists in understanding the nonlinear physics of structure formation, which is dominated by gravity on scales larger than a few Mpc. By making progress in this understanding, we can unlock a rich trove of information on fundamental physics from large-scale structure. The research goals will be pursued on all three fronts of analytical theory, numerical simulations, and confrontation with data. With space missions, such as Planck and Euclid, as well as ground-based surveys delivering data sets of unprecedented size and quality at this very moment, the proposed research is especially timely. It will make key contributions towards maximizing the science output of these experiments, deepen our understanding of the laws of physics, and uncover our cosmological origins.

Over the past two decades, a data-driven revolution has occurred in our understanding of the origin and evolution of our Universe and the structure within it. During this period, cosmology has evolved from a speculative branch of theoretical physics into precision science at the intersection of gravity, particle- and astrophysics. Despite all we have learned, we still do not understand why the Universe accelerates, and how the structure in the Universe originated. Recent breakthrough research, with leading contributions by the PI of this proposal, has shown that we can make progress on these questions using observations of the large-scale structure and its tracers, galaxies. This opens up a fascinating, new interdisciplinary research field: probing Gravity and Inflation with Galaxies. The goal of the proposed research is to first, probe our theory of gravity, General Relativity, on cosmological scales. Second, it aims to shed light on the origin of the initial seed fluctuations out of which all structure in the Universe formed, by constraining the physics and energy scale of inflation. While seemingly unrelated, the main challenge in both research directions consists in understanding the nonlinear physics of structure formation, which is dominated by gravity on scales larger than a few Mpc. By making progress in this understanding, we can unlock a rich trove of information on fundamental physics from large-scale structure. The research goals will be pursued on all three fronts of analytical theory, numerical simulations, and confrontation with data. With space missions, such as Planck and Euclid, as well as ground-based surveys delivering data sets of unprecedented size and quality at this very moment, the proposed research is especially timely. It will make key contributions towards maximizing the science output of these experiments, deepen our understanding of the laws of physics, and uncover our cosmological origins.

Max ERC Funding

1 330 625 €

Duration

Start date: 2016-09-01, End date: 2021-08-31

Project acronymRadFeedback

ProjectThe radiative interstellar medium

Researcher (PI)Stefanie Walch-Gassner

Host Institution (HI)UNIVERSITAET ZU KOELN

Call DetailsStarting Grant (StG), PE9, ERC-2015-STG

SummaryThe pressure, radiation, and ionization from the warm (UV emitting) and hot (X-ray emitting) gas has a significant impact on the cold, star-forming interstellar medium. We propose to carry out a comprehensive 3D study of the turbulent, multi-phase ISM in different environments that includes, for the first time, a proper treatment of UV and X-ray emission from stellar (primary) sources and extended (secondary) sources like cooling shock fronts and evaporating clouds. We do this by means of massively parallel, high-resolution 3D simulations that capture the complex interplay of gravity, magnetic fields, feedback from massive stars (ionizing radiation, radiation pressure, stellar winds, supernovae), heating and cooling including X-rays and cosmic rays, and chemistry. We are developing a novel, original and highly efficient method to accurately treat the transfer of radiation from multiple point and extended sources in the 3D simulations. Radiation and chemistry will be coupled to achieve self-consistent heating, cooling, and ionization rates. Moreover, accurate synthetic observations covering the large dynamic range from X-rays down to radio emission will be generated to set the results in the proper observational context. This will enable us to address the key science questions: How efficient is stellar feedback in different environments and which feedback process is dominant? What is the precise role of UV radiation and X-rays, also from secondary sources? Are the observations following the key dynamical players? How do we best interpret ISM observations from ALMA, SKA, or ATHENA? How do we assist in designing future observations? With the resources requested here we will perform the most self-consistent theoretical study of the multi-phase ISM so far, thus building up a leading group for ISM research in Europe. To stimulate worldwide scientific activities and interactions we will make all data available to the community through an open-access web interface.

The pressure, radiation, and ionization from the warm (UV emitting) and hot (X-ray emitting) gas has a significant impact on the cold, star-forming interstellar medium. We propose to carry out a comprehensive 3D study of the turbulent, multi-phase ISM in different environments that includes, for the first time, a proper treatment of UV and X-ray emission from stellar (primary) sources and extended (secondary) sources like cooling shock fronts and evaporating clouds. We do this by means of massively parallel, high-resolution 3D simulations that capture the complex interplay of gravity, magnetic fields, feedback from massive stars (ionizing radiation, radiation pressure, stellar winds, supernovae), heating and cooling including X-rays and cosmic rays, and chemistry. We are developing a novel, original and highly efficient method to accurately treat the transfer of radiation from multiple point and extended sources in the 3D simulations. Radiation and chemistry will be coupled to achieve self-consistent heating, cooling, and ionization rates. Moreover, accurate synthetic observations covering the large dynamic range from X-rays down to radio emission will be generated to set the results in the proper observational context. This will enable us to address the key science questions: How efficient is stellar feedback in different environments and which feedback process is dominant? What is the precise role of UV radiation and X-rays, also from secondary sources? Are the observations following the key dynamical players? How do we best interpret ISM observations from ALMA, SKA, or ATHENA? How do we assist in designing future observations? With the resources requested here we will perform the most self-consistent theoretical study of the multi-phase ISM so far, thus building up a leading group for ISM research in Europe. To stimulate worldwide scientific activities and interactions we will make all data available to the community through an open-access web interface.